SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '588dfeab8daee2d4c0a68152a6062c1160e925e6573a93a051af34f7bc948093' 
  AND token = 'GT6XcEEDQj9WZpexGXJP/Pm3ELqHEBzsuUUghLxR4d8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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