SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bdcba8feb920cff20478f3b020dfec13503f3d5d0124fb2d0e345076ba587b1' 
  AND token = 'yAyWCu7oa+KjLkfrqTUDujT3Vyz75GAYo4KyGIDy4Yo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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