SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f74d5be5902796b960dbc61f4ff77584385898db1b79b1ec77f450a9f712b70e' 
  AND token = 'aZqSQgLh7pVMDNUfitJ0mfC0/W9nhedhui6KOp+eHe0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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