SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c88c6f10db60923ac226903e8523e1bd491620f0a7b85131c826b8518be5fae' 
  AND token = '2B6CRGk3IxT1+3UJa4d6ElTHSK/fI//VY122b4T6+rE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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