SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c290f8f669e6a62f02ad102619db3ee3edb2b480fda17f464b8007853c3e904' 
  AND token = 'K/2hZJr97DB4t3BuTxBw26sLovhlJnwAPVST64JwZgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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