SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '702418632b934a8f4e287ff08c1173ff708fcfad2d9f5b8cd79529dcfd1a20a3' 
  AND token = 'pMBWP/cbBvcreZxfh3FHGS3gjxdVSAH5qSc+kwnG6Us=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}