SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '332c9c731e398dfefaaaeb93d57967f9debcf8cdabcfe419bff2fcc540a0b739' 
  AND token = 'VTpcdZATEilsY7knZBaF8KQB1rBONhLEQoSKyi+o3oc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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