SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9d544406e4e8e3520ab951c6743f740a496589f6fa2ed96a8b54bc4f2eabc32' 
  AND token = 'e+LIsmUqbukmyYd3QX3Xi+LnCmwEnWZrprQB10mf12c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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