SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b96db3b07758fadf300fd6c5625e66623cc17d3dde902ec149250300526e633c' 
  AND token = 'w9ejJSkEzl0eW8vxxNdzLzTRy96YSyyt/qcVHGQQtHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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