SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c21095bbcabc547a48784c072305125f1f1dbff6a2ebe0cd8d3bcf7495ef438' 
  AND token = '/BVsLjy7+nyN0XYPqgxiQuQl7R7F91VrXSUZYAHabCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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