SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68a2d3688417422b3664cc0a40dedbafc53c765c5d0a8fa3273eba574875bcba' 
  AND token = 'fLPf+PDJFOISYx93nJgH4BI0sI73i5cyjZmLBl603zA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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