SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f617b95d6691ba1d13bfc34560c94c96bc2970df843ccbf3f0e8a1894a5094d2' 
  AND token = 'dIrbIK5Qhl0NnZzzwqBOimo/B+WZ0ARNNrxTOP1fV24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}