SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a63e70154e039f6c2d44713066c0ed57fd1bfcecde5113d3a98b8b0c279d157' 
  AND token = 'BF4LnKp7RsBLgwpOO1+DD283rloSK2K+1uN0oYyIrpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}