SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6eb434aff6e9ee20bbd284eb23bedf245ab05512f1fa13892069137f67380536' 
  AND token = 'kJIpK2TSApqxwLIDLV+Y9kNWbXd6BamAItxAn/ay9N0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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