SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d9d16692e1b1fbe770b54203518bf729d3a47ec26df40f846c4137ce4963c86' 
  AND token = 'kQCCERBuTdDIRRSlMjwBHiw+m7bcU/KSdzM+bAWXjNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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