SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d78902f1b90d1a0e0ca6863d19703b91d9953c12b45307d7a09e40f6dc91ef8' 
  AND token = 'ORCqwgyAh/XdtRH+Jl6CxS9G9RhZFj6jYNpm1j/No1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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