SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af44863bef733236597266a2ed0bce1d10763f8ea5a0b0947f69269ad81e3474' 
  AND token = 'KkVIlK6vDRSh5CrKAVMwTuVBrXtMYVy4FwnrTDd3So0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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