SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87943265c528520000b0150ffe6a5d6e70ef3bbd37db76b1d22b1123af4a6ffd' 
  AND token = 'nEo2R1JY4gtctQ75FIIKXCD3HfbXxG/Am+Way6094Ps=' 
  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"
    }
  }
}