SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0dce1faa5e19469c0f14530b3f0bf3aafa6dafad7ab42a258e8b7d5385d2d7d' 
  AND token = 'SgsLoOqyCnLnMDaWeommcNtgvSMvdGoHZo7PbY5sCqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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