SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e96eeeda0a16c5a067b236d8404fca367bde7e35b04693682f062f2ff271a6e' 
  AND token = 'xNms77wwyfWrTBrHqCfnD4Qd4Rw4YAMDfz4jj+YOmtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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