SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd77dca03f3b35c9fc8464cf643e611d7d2f9937547762d588c52103fda8a2547' 
  AND token = 'ZTz9kHoV1Uk4YKK+T3uRkuAAQlPhIAaKUQ+gqlkVP+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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