SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dcbd853ada0b7e4531efbfe056e2d1c6744cc83283bd80b81f482c182a8a1e8' 
  AND token = 'v750i2byZikKZt7ylmG/w73/7xh9a9mSWW4OP5VCG7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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