SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd8c91ba6fca879108372064c75e3bc4135e3c35da912d97f074929c80361eb76' 
  AND token = 'SO0ot7R02jbToFGw+CHv6uu5AnYNF/ziCNnqtkl+1kI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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