SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20f6013f622d12746a0d155d357fe7b1883ac70d783c1d9462bf5fd4fb093684' 
  AND token = 'KFas+84kr81NpM71PmudkZSXByHhZuoX7aE0IqO+wB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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