SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1551ba71fe19adcd6239135cf340d318396d65cac5c3d353cfd41e90ca329ac7' 
  AND token = 'bTn5/895+BvyComWDH2NbXnz8WrgH46z7MPBakAKbMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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