SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9eae598f8deff776a354098b0f6b7dd1b3942d25d13a2aa88a673249c510e2a1' 
  AND token = 'JQhtb77Bwg4N2lwHBlP1ewtTCUXg8yId9jGA/KwghPc=' 
  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"
    }
  }
}