SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0a57329882475da84d54204e1cea909f0835cca5d31f61122ea94ff5aeb9d9a' 
  AND token = 'ovTId21/gkcxP2lMQBBYbhHyc2vcqqa3luYLEwtvkU8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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