SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a35be6584c4ebd5c91506c2dfc917b77914d2458c6d73e38e12380078aec4e5a' 
  AND token = 'WJ9uEnF5EizaREXK00lX457G4A3hoqfdStdxBSI+i+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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