SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bce71773f60e8fded59f94622f8b9ae38f3b23d61c55483fef1e8998ecbedfed' 
  AND token = 'LqUs9WhUBhzsgUOvZZppSjYGNecATKAaygQ2YG7H2d4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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