SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d3789e25b5fbf4cdde283ad66b548e924573a8e6cf1a48c14e4099af6f60346' 
  AND token = 'qcoSf6V75KohO2Ld7bPBwat7psDKvNt7+MQ3fJz/m3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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