SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '90c19460f93432c551e71e445502deca2e2d1e32f163d1eb179b1c0f1f8a9cde' 
  AND token = 'lL2G/5eNdGp7JXC+K6scc5oP558JJohEgfow69Yq8aY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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