SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b82bb15edb15996aa23acc2b66c8ce03ba7c897cf440a68466f06d8171f91f6' 
  AND token = 'a5ssruiBz+FQRXgWx5QeOG6k3posNpuS75IA+Q8WOPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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