SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ee230660c46be0bc34ee46cdf28d00e6ac463ad868bbaffb941213747f2aa21' 
  AND token = 'DqfaDV19z3NE9mxEHThnK1tlqV639dRXOUDus4qZ09g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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