SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '99d195d78537cd8a2dc1e37683a019888ce079db00bac336a43cf8beac02b101' 
  AND token = '2+rGaxoEtdEvFLoqbmEBO8AbQGO+8bfJ5g8GqVfIYKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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