SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e9902793f984708869dfe27448a637fa4ce5812188c9ef83e7168d667bbbc83' 
  AND token = 'rSydkbvzIjptxLHBfBC21beVWncDQ3I5bHI51crrMjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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