SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31020c61921dcf4432a0964bd2070ffae9c1f5ad44156524fa6690dbf17e0a2f' 
  AND token = 'jAwVYISQuaqrUNGZpg584aIAIgC/0grtGS+5oRlfHUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}