SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16510c6437fb81cde004ab8beff5a769051e9d4e6b378dab7931fa8e8993e4bf' 
  AND token = 'qB/GE3nFHxz8dl/RwZLGcIZ7+tlfMgHjNPjjEZthC5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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