SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3971da8cb3d4223ee652405abaa53627723de4c4651cbc906274dbde38062740' 
  AND token = 'Hc8mcXFvD6h0zk7HNFj8wGEGg7d2TkipjNsfZrh3XcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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