SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81c26772b0c4f904d0d6bf962a85810fce9e3fe77dfe4122d935861ad9f02ce5' 
  AND token = '6w6hE7EZgBB/ZqgLGRUQGLl/t+mYe35i/MFSH/AE/R8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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