SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3eee0f7572d321460558438b84a36031252ae9c6aa0a84af9e637b9510d287f4' 
  AND token = 'kb2qbaYby8KH3+0bixAy2QTAh0qhi9iT9tZ1Z85M1r0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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