SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4fe9e725ff2a0eb0358bc6f5100525ecc70d968ab7c46656e2ba1ed1de19b4e' 
  AND token = 'sS6sTCafHw0xW1auqGXI9pM7gitT5AtwNMe3KxTrUv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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