SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '178f649bcc08bc3dfccea156262a537015a8d2d9fcc98f8f2c3f286e4b394e99' 
  AND token = 'DBvCyU+fBxXBRU1frhDfuP+K3CqCJCvPGGEQeJfKGWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}