SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '450d1826cb63c7d5b4f19248178f58a50829d922897864b13fb6e52e18a51f91' 
  AND token = 'uq+v2m6oiCkF+kX2DKGh4TreuMess7zf1LDqvSBBZ2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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