SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'de8ecd9036283084837c6fad3d8a066cb9684c47df7f624e403b961f1957a387' 
  AND token = 'NveRAjOlux4Ku+XEASqvxEn1u+oDec2ToOrXuRH3AS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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