SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '327581305792ac3eb8441f538e6c4912ac73fbd6b9655fb7e12ac8b3d5110cfb' 
  AND token = 'QKRIb4UGV3AR70a0jE19A73t2bF0ReO7OXBwEC+NWYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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