SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b422a45ce4179eea473b3fdcc011b42f285a707d893dbf2fc2447cb9bbefd83' 
  AND token = 'JUrk6JpG2QfyRTRDqWfyxKBxzZ2FUWq3JJWyWFSjfBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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