SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a173e0c7d6b11f0847e71e19e287bd4f7577c2158fe5ae9b788f86ab5428fffc' 
  AND token = 'YLeXSMPX+3KwK/Chv2SjrPAFispBxG4gnbK3BAV4H08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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