SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3adc1707d84bf0c2b0e5af99bc64a4521cc426ccf997d82ee0a1ae6d10b0b245' 
  AND token = 'bMqTebCXzv6sTiV7DoXPExpq0kgvIUrFlmf+Ey1ck3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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