SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc4370f30bf53e819f147539072a9bf2cf32062451eaf3a344a1d3bc04b3b706' 
  AND token = '2kCSXMqgH4hVmQ6DNnBVhCJ91xlSz9Cwr6YFg4usKxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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