SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19708725b1fa23d899bb7cc6274f0e608acfbae165aecdf13382dc5c522154ac' 
  AND token = '5bIpwxvf+pFPbgxy+apQYgaV4K7N5BoCHtiJWEeoJzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}