SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c76068d0bbe82eb4d374a81edd42942040e1bff000c49875aa485c5c5166180' 
  AND token = '4w2TflOCJyTBfa9BC6N5bidur+8rdJ2Ru6v4tvMRF3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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