SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79faa68a1d32aac355bd1dd49a5224b63c6d6542063540560485180a3a1bf5fc' 
  AND token = 'z4PGC59OJwwna490ktYl1YrZpCM/GP4rbVd0EuJEpdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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