SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15f98c53be17fa37bc94157487031d5f88ef55ce86518cdb601ca862cdfd196e' 
  AND token = 'LvuSmw08vbzpNbQLzBNqfPnnFCR3Au3IYJkL1xBP/Rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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