SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b584c063c4758087e59aa3c354a1b37854697ebb4964e111fd5927dc666a690' 
  AND token = 'MhB2YgVB9zIMnLvjNlh7JOPHc3xReT5E/mxnBSskfzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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