SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d3adb3b474d3048c52dcb21a5394a387edd3304703284119853c2bced2b385f' 
  AND token = '7anYEDUsToI/NNRlJMH7RcpRY/9w1VMuhrrBFa7Qn94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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