SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1dc53f398f171eee355196cdabcfbc67229e143c8596be22772d04fe60c28d0b' 
  AND token = 'zGeWaFWR24heISF6UQLMAJGZXqgIXZ7Nob+qdpUASQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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