SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea284bf4a278757eb21073498c286a24dd85d0edcec9a61ab1b8be957b1cdca9' 
  AND token = 'Pupp1dYtv6+JD0VylezFMw97j/6SUZMyY+KQg/DWMUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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