SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '547f19ddc69883e83782bfccce850dcc93ab29c6d83fbe2511a573b06c0ac402' 
  AND token = 'jT37xKWBM51nKBIb7WC1EkUWtHGCV8AnRpxduPIJ3IE=' 
  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"
    }
  }
}