SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b34a118a89748b39ef00e9e4d9202e37e0727f4f5dd471555361a32d862e7877' 
  AND token = 'NKDVoYpH/vl67ALFJDKQ2Yv+yRpbmTNjig04CNcrOy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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