SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a154137f759d22f11752ad587ffad36b80d0b37cffa3abc4deed6b8d6946ee83' 
  AND token = 'n3D3F563vVPjvuPH5ag7Q05JTThWPjr/AdK7rEdJuRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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