SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c375e7a012f1c52d3696ecff6729bf50f6e485bd7d642e1be3be2103e09d4fce' 
  AND token = 'YdMzFDtnkXwoz8/WqJoDIa+zurRLFPaYWMGlf1aS/uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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