SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7468ecd0ebcc4aa8934e88bf153d08187da32496be44bb7ee85e4dace6e223c' 
  AND token = 'mdIcW9om6YQDwPFp7KNILPinQt10MUecPb1u7qwyJkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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