SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af8bf61f66301d3c767bbdaf77b737d17565879ff3e41c159fcb03eb4fd724a3' 
  AND token = 'wleGwBgsZA+j+FjjOlJ8MFsiWyemBpVXzQqIFTCQqX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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