SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31ca8855fd8a5bcb1d2eb09d07de1e51c4b54580f1ce6a4a2d412558b5eeb70c' 
  AND token = '8odSVutAutWmtRwoDLAmZ3fBAMqaGF/q09200UZF8f8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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