SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f17b362ad156eeb58cffff6c00916e10379dd0ceff8ee3c19d130e3279294ab4' 
  AND token = 'C/F+EUPKDn7QtAtnQUFrVGFDLjexeP6HcTgql9l/y4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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