SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f780f426c7f27fdbe3aebb6f7b03eb401d94e146adb08a32a7a8ae0c32863b0' 
  AND token = 'kCiTgvMTBcWjTL/D/izNQgLunCCdpcFRCLkinfX8Cs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}