SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f80adfd3b73c3795527cb9c8f68cebba19a25f515b57a0b310f9930a410b78d3' 
  AND token = 'gQcnLxofOXWtu4h34oM3Bmsz4mWJTXcRvCnK1jSBHVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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