SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b6f1a1cdf67473f7a7757b672cd576bfc6955b2cf00ea66aaacb48f6ddc8b66' 
  AND token = 'A49+nY5K0gJhdNp1Vv1Cw/vm/mZHL/HlGPOHSdugYek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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