SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcd681aa5adc0f6699c0009b7f3172af35c52db740b5ff02524a9a802fee96d9' 
  AND token = 'sLTrGAWb/PvzmWfWLmRQd5+2es3TBV/yAAPm3g2n7Bc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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