SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68de1d46b3c7204b54e7a88a0d015a97249f6e8329b956929852c5bf94f2a653' 
  AND token = 'Je9aTENGhCniMAJG1B/euS+mOjKCoBq+fOmBWjJzEL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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