SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f13f9838d8ee69772186d635a50edfb02b895e49dd4b0f4f3becdfbcd5ce3954' 
  AND token = 'wmQgQSo5oOTzsJGJ9/Hw1dz5nWCNKNmGMVhm5VL+Q0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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