SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4a02e4bc389ab1899be9e6af67e225fa7d524f7222eb681c0db2354d5b90150' 
  AND token = 'rkjPv+ps3cZfBVHRfQzFExpOlqmNMgrAeKY3+ZvS/C0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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