SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b26a59f9acd354c85ff80a1ad558e81b04f8de1dac7839aae3d237e7db3a796c' 
  AND token = 'H6eMhBWcLpBClsRQYzGuhiW6ZZHkvfmxKuO+TBJeaw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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