SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81858c5e9505c8d892ddb2150b7f431d8fd83a11ca96ebf684606fcd6d621013' 
  AND token = 'hpWmmDySw5+9+chv1J+tn0wN3aHEoRxlrfiNDxP8qrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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