SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '046513233fdd0fcbe6173da13783ff580aca50b23c481416c89b9def229ad6f2' 
  AND token = 'kAWORjRRvPjzxXeS1GYvruDFn3hypmZyTOKY5D5YtgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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