SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6093639fd7cd756c43f119b0c597ecdefd8dd83464b7a3bfa6015af427997ce' 
  AND token = 'ofIEbxjc+UYapVY1SLR4euyuiIEoomzC08AOW2QSUPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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