SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb154160326ad441105475ccae5b482eb92fe7e45f72aed5204e25ba332da9f2' 
  AND token = 'g6IB0HvAirrOX47yukVzZJcC1YYt1ymwJPwXsZlhqQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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