SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eba9a5b2bc830092339dd365ec32b148b90791cf27a41da94d4dc25c61033450' 
  AND token = 'MAYpkIyWp0aVyTY8ZB0siFV+VtNjqbXdlRuQCwcyL10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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