SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bc61f8fa573fe220dd480aa8ecb564a29567da4f33ee82988648932e948fa237' 
  AND token = 'lB63vT114MkVoJS6pr0o43MhklLwmvJ1NanisPsAnyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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